drivers/base/firmware_class.c

   1 /*
   2  * firmware_class.c - Multi purpose firmware loading support
   3  *
   4  * Copyright (c) 2003 Manuel Estrada Sainz
   5  *
   6  * Please see Documentation/firmware_class/ for more information.
   7  *
   8  */
   9
  10 #include <linux/capability.h>
  11 #include <linux/device.h>
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/timer.h>
  15 #include <linux/vmalloc.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/bitops.h>
  18 #include <linux/mutex.h>
  19 #include <linux/kthread.h>
  20
  21 #include <linux/firmware.h>
  22 #include "base.h"
  23
  24 #define to_dev(obj) container_of(obj, struct device, kobj)
  25
  26 MODULE_AUTHOR("Manuel Estrada Sainz");
  27 MODULE_DESCRIPTION("Multi purpose firmware loading support");
  28 MODULE_LICENSE("GPL");
  29
  30 enum {
  31         FW_STATUS_LOADING,
  32         FW_STATUS_DONE,
  33         FW_STATUS_ABORT,
  34 };
  35
  36 static int loading_timeout = 60;        /* In seconds */
  37
  38 /* fw_lock could be moved to 'struct firmware_priv' but since it is just
  39  * guarding for corner cases a global lock should be OK */
  40 static DEFINE_MUTEX(fw_lock);
  41
  42 struct firmware_priv {
  43         char fw_id[FIRMWARE_NAME_MAX];
  44         struct completion completion;
  45         struct bin_attribute attr_data;
  46         struct firmware *fw;
  47         unsigned long status;
  48         int alloc_size;
  49         struct timer_list timeout;
  50 };
  51
  52 static void
  53 fw_load_abort(struct firmware_priv *fw_priv)
  54 {
  55         set_bit(FW_STATUS_ABORT, &fw_priv->status);
  56         wmb();
  57         complete(&fw_priv->completion);
  58 }
  59
  60 static ssize_t
  61 firmware_timeout_show(struct class *class, char *buf)
  62 {
  63         return sprintf(buf, "%d\n", loading_timeout);
  64 }
  65
  66 /**
  67  * firmware_timeout_store - set number of seconds to wait for firmware
  68  * @class: device class pointer
  69  * @buf: buffer to scan for timeout value
  70  * @count: number of bytes in @buf
  71  *
  72  *      Sets the number of seconds to wait for the firmware.  Once
  73  *      this expires an error will be returned to the driver and no
  74  *      firmware will be provided.
  75  *
  76  *      Note: zero means 'wait forever'.
  77  **/
  78 static ssize_t
  79 firmware_timeout_store(struct class *class, const char *buf, size_t count)
  80 {
  81         loading_timeout = simple_strtol(buf, NULL, 10);
  82         if (loading_timeout < 0)
  83                 loading_timeout = 0;
  84         return count;
  85 }
  86
  87 static CLASS_ATTR(timeout, 0644, firmware_timeout_show, firmware_timeout_store);
  88
  89 static void fw_dev_release(struct device *dev);
  90
  91 static int firmware_uevent(struct device *dev, struct kobj_uevent_env *env)
  92 {
  93         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
  94
  95         if (add_uevent_var(env, "FIRMWARE=%s", fw_priv->fw_id))
  96                 return -ENOMEM;
  97         if (add_uevent_var(env, "TIMEOUT=%i", loading_timeout))
  98                 return -ENOMEM;
  99
 100         return 0;
 101 }
 102
 103 static struct class firmware_class = {
 104         .name           = "firmware",
 105         .dev_uevent     = firmware_uevent,
 106         .dev_release    = fw_dev_release,
 107 };
 108
 109 static ssize_t firmware_loading_show(struct device *dev,
 110                                      struct device_attribute *attr, char *buf)
 111 {
 112         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 113         int loading = test_bit(FW_STATUS_LOADING, &fw_priv->status);
 114         return sprintf(buf, "%d\n", loading);
 115 }
 116
 117 /**
 118  * firmware_loading_store - set value in the 'loading' control file
 119  * @dev: device pointer
 120  * @attr: device attribute pointer
 121  * @buf: buffer to scan for loading control value
 122  * @count: number of bytes in @buf
 123  *
 124  *      The relevant values are:
 125  *
 126  *       1: Start a load, discarding any previous partial load.
 127  *       0: Conclude the load and hand the data to the driver code.
 128  *      -1: Conclude the load with an error and discard any written data.
 129  **/
 130 static ssize_t firmware_loading_store(struct device *dev,
 131                                       struct device_attribute *attr,
 132                                       const char *buf, size_t count)
 133 {
 134         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 135         int loading = simple_strtol(buf, NULL, 10);
 136
 137         switch (loading) {
 138         case 1:
 139                 mutex_lock(&fw_lock);
 140                 if (!fw_priv->fw) {
 141                         mutex_unlock(&fw_lock);
 142                         break;
 143                 }
 144                 vfree(fw_priv->fw->data);
 145                 fw_priv->fw->data = NULL;
 146                 fw_priv->fw->size = 0;
 147                 fw_priv->alloc_size = 0;
 148                 set_bit(FW_STATUS_LOADING, &fw_priv->status);
 149                 mutex_unlock(&fw_lock);
 150                 break;
 151         case 0:
 152                 if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {
 153                         complete(&fw_priv->completion);
 154                         clear_bit(FW_STATUS_LOADING, &fw_priv->status);
 155                         break;
 156                 }
 157                 /* fallthrough */
 158         default:
 159                 printk(KERN_ERR "%s: unexpected value (%d)\n", __FUNCTION__,
 160                        loading);
 161                 /* fallthrough */
 162         case -1:
 163                 fw_load_abort(fw_priv);
 164                 break;
 165         }
 166
 167         return count;
 168 }
 169
 170 static DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 171
 172 static ssize_t
 173 firmware_data_read(struct kobject *kobj, struct bin_attribute *bin_attr,
 174                    char *buffer, loff_t offset, size_t count)
 175 {
 176         struct device *dev = to_dev(kobj);
 177         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 178         struct firmware *fw;
 179         ssize_t ret_count = count;
 180
 181         mutex_lock(&fw_lock);
 182         fw = fw_priv->fw;
 183         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 184                 ret_count = -ENODEV;
 185                 goto out;
 186         }
 187         if (offset > fw->size) {
 188                 ret_count = 0;
 189                 goto out;
 190         }
 191         if (offset + ret_count > fw->size)
 192                 ret_count = fw->size - offset;
 193
 194         memcpy(buffer, fw->data + offset, ret_count);
 195 out:
 196         mutex_unlock(&fw_lock);
 197         return ret_count;
 198 }
 199
 200 static int
 201 fw_realloc_buffer(struct firmware_priv *fw_priv, int min_size)
 202 {
 203         u8 *new_data;
 204         int new_size = fw_priv->alloc_size;
 205
 206         if (min_size <= fw_priv->alloc_size)
 207                 return 0;
 208
 209         new_size = ALIGN(min_size, PAGE_SIZE);
 210         new_data = vmalloc(new_size);
 211         if (!new_data) {
 212                 printk(KERN_ERR "%s: unable to alloc buffer\n", __FUNCTION__);
 213                 /* Make sure that we don't keep incomplete data */
 214                 fw_load_abort(fw_priv);
 215                 return -ENOMEM;
 216         }
 217         fw_priv->alloc_size = new_size;
 218         if (fw_priv->fw->data) {
 219                 memcpy(new_data, fw_priv->fw->data, fw_priv->fw->size);
 220                 vfree(fw_priv->fw->data);
 221         }
 222         fw_priv->fw->data = new_data;
 223         BUG_ON(min_size > fw_priv->alloc_size);
 224         return 0;
 225 }
 226
 227 /**
 228  * firmware_data_write - write method for firmware
 229  * @kobj: kobject for the device
 230  * @bin_attr: bin_attr structure
 231  * @buffer: buffer being written
 232  * @offset: buffer offset for write in total data store area
 233  * @count: buffer size
 234  *
 235  *      Data written to the 'data' attribute will be later handed to
 236  *      the driver as a firmware image.
 237  **/
 238 static ssize_t
 239 firmware_data_write(struct kobject *kobj, struct bin_attribute *bin_attr,
 240                     char *buffer, loff_t offset, size_t count)
 241 {
 242         struct device *dev = to_dev(kobj);
 243         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 244         struct firmware *fw;
 245         ssize_t retval;
 246
 247         if (!capable(CAP_SYS_RAWIO))
 248                 return -EPERM;
 249
 250         mutex_lock(&fw_lock);
 251         fw = fw_priv->fw;
 252         if (!fw || test_bit(FW_STATUS_DONE, &fw_priv->status)) {
 253                 retval = -ENODEV;
 254                 goto out;
 255         }
 256         retval = fw_realloc_buffer(fw_priv, offset + count);
 257         if (retval)
 258                 goto out;
 259
 260         memcpy(fw->data + offset, buffer, count);
 261
 262         fw->size = max_t(size_t, offset + count, fw->size);
 263         retval = count;
 264 out:
 265         mutex_unlock(&fw_lock);
 266         return retval;
 267 }
 268
 269 static struct bin_attribute firmware_attr_data_tmpl = {
 270         .attr = {.name = "data", .mode = 0644},
 271         .size = 0,
 272         .read = firmware_data_read,
 273         .write = firmware_data_write,
 274 };
 275
 276 static void fw_dev_release(struct device *dev)
 277 {
 278         struct firmware_priv *fw_priv = dev_get_drvdata(dev);
 279
 280         kfree(fw_priv);
 281         kfree(dev);
 282
 283         module_put(THIS_MODULE);
 284 }
 285
 286 static void
 287 firmware_class_timeout(u_long data)
 288 {
 289         struct firmware_priv *fw_priv = (struct firmware_priv *) data;
 290         fw_load_abort(fw_priv);
 291 }
 292
 293 static inline void fw_setup_device_id(struct device *f_dev, struct device *dev)
 294 {
 295         snprintf(f_dev->bus_id, BUS_ID_SIZE, "firmware-%s", dev->bus_id);
 296 }
 297
 298 static int fw_register_device(struct device **dev_p, const char *fw_name,
 299                               struct device *device)
 300 {
 301         int retval;
 302         struct firmware_priv *fw_priv = kzalloc(sizeof(*fw_priv),
 303                                                 GFP_KERNEL);
 304         struct device *f_dev = kzalloc(sizeof(*f_dev), GFP_KERNEL);
 305
 306         *dev_p = NULL;
 307
 308         if (!fw_priv || !f_dev) {
 309                 printk(KERN_ERR "%s: kmalloc failed\n", __FUNCTION__);
 310                 retval = -ENOMEM;
 311                 goto error_kfree;
 312         }
 313
 314         init_completion(&fw_priv->completion);
 315         fw_priv->attr_data = firmware_attr_data_tmpl;
 316         strlcpy(fw_priv->fw_id, fw_name, FIRMWARE_NAME_MAX);
 317
 318         fw_priv->timeout.function = firmware_class_timeout;
 319         fw_priv->timeout.data = (u_long) fw_priv;
 320         init_timer(&fw_priv->timeout);
 321
 322         fw_setup_device_id(f_dev, device);
 323         f_dev->parent = device;
 324         f_dev->class = &firmware_class;
 325         dev_set_drvdata(f_dev, fw_priv);
 326         f_dev->uevent_suppress = 1;
 327         retval = device_register(f_dev);
 328         if (retval) {
 329                 printk(KERN_ERR "%s: device_register failed\n",
 330                        __FUNCTION__);
 331                 goto error_kfree;
 332         }
 333         *dev_p = f_dev;
 334         return 0;
 335
 336 error_kfree:
 337         kfree(fw_priv);
 338         kfree(f_dev);
 339         return retval;
 340 }
 341
 342 static int fw_setup_device(struct firmware *fw, struct device **dev_p,
 343                            const char *fw_name, struct device *device,
 344                            int uevent)
 345 {
 346         struct device *f_dev;
 347         struct firmware_priv *fw_priv;
 348         int retval;
 349
 350         *dev_p = NULL;
 351         retval = fw_register_device(&f_dev, fw_name, device);
 352         if (retval)
 353                 goto out;
 354
 355         /* Need to pin this module until class device is destroyed */
 356         __module_get(THIS_MODULE);
 357
 358         fw_priv = dev_get_drvdata(f_dev);
 359
 360         fw_priv->fw = fw;
 361         retval = sysfs_create_bin_file(&f_dev->kobj, &fw_priv->attr_data);
 362         if (retval) {
 363                 printk(KERN_ERR "%s: sysfs_create_bin_file failed\n",
 364                        __FUNCTION__);
 365                 goto error_unreg;
 366         }
 367
 368         retval = device_create_file(f_dev, &dev_attr_loading);
 369         if (retval) {
 370                 printk(KERN_ERR "%s: device_create_file failed\n",
 371                        __FUNCTION__);
 372                 goto error_unreg;
 373         }
 374
 375         if (uevent)
 376                 f_dev->uevent_suppress = 0;
 377         *dev_p = f_dev;
 378         goto out;
 379
 380 error_unreg:
 381         device_unregister(f_dev);
 382 out:
 383         return retval;
 384 }
 385
 386 static int
 387 _request_firmware(const struct firmware **firmware_p, const char *name,
 388                  struct device *device, int uevent)
 389 {
 390         struct device *f_dev;
 391         struct firmware_priv *fw_priv;
 392         struct firmware *firmware;
 393         int retval;
 394
 395         if (!firmware_p)
 396                 return -EINVAL;
 397
 398         *firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);
 399         if (!firmware) {
 400                 printk(KERN_ERR "%s: kmalloc(struct firmware) failed\n",
 401                        __FUNCTION__);
 402                 retval = -ENOMEM;
 403                 goto out;
 404         }
 405
 406         retval = fw_setup_device(firmware, &f_dev, name, device, uevent);
 407         if (retval)
 408                 goto error_kfree_fw;
 409
 410         fw_priv = dev_get_drvdata(f_dev);
 411
 412         if (uevent) {
 413                 if (loading_timeout > 0) {
 414                         fw_priv->timeout.expires = jiffies + loading_timeout * HZ;
 415                         add_timer(&fw_priv->timeout);
 416                 }
 417
 418                 kobject_uevent(&f_dev->kobj, KOBJ_ADD);
 419                 wait_for_completion(&fw_priv->completion);
 420                 set_bit(FW_STATUS_DONE, &fw_priv->status);
 421                 del_timer_sync(&fw_priv->timeout);
 422         } else
 423                 wait_for_completion(&fw_priv->completion);
 424
 425         mutex_lock(&fw_lock);
 426         if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status)) {
 427                 retval = -ENOENT;
 428                 release_firmware(fw_priv->fw);
 429                 *firmware_p = NULL;
 430         }
 431         fw_priv->fw = NULL;
 432         mutex_unlock(&fw_lock);
 433         device_unregister(f_dev);
 434         goto out;
 435
 436 error_kfree_fw:
 437         kfree(firmware);
 438         *firmware_p = NULL;
 439 out:
 440         return retval;
 441 }
 442
 443 /**
 444  * request_firmware: - send firmware request and wait for it
 445  * @firmware_p: pointer to firmware image
 446  * @name: name of firmware file
 447  * @device: device for which firmware is being loaded
 448  *
 449  *      @firmware_p will be used to return a firmware image by the name
 450  *      of @name for device @device.
 451  *
 452  *      Should be called from user context where sleeping is allowed.
 453  *
 454  *      @name will be used as $FIRMWARE in the uevent environment and
 455  *      should be distinctive enough not to be confused with any other
 456  *      firmware image for this or any other device.
 457  **/
 458 int
 459 request_firmware(const struct firmware **firmware_p, const char *name,
 460                  struct device *device)
 461 {
 462         int uevent = 1;
 463         return _request_firmware(firmware_p, name, device, uevent);
 464 }
 465
 466 /**
 467  * release_firmware: - release the resource associated with a firmware image
 468  * @fw: firmware resource to release
 469  **/
 470 void
 471 release_firmware(const struct firmware *fw)
 472 {
 473         if (fw) {
 474                 vfree(fw->data);
 475                 kfree(fw);
 476         }
 477 }
 478
 479 /* Async support */
 480 struct firmware_work {
 481         struct work_struct work;
 482         struct module *module;
 483         const char *name;
 484         struct device *device;
 485         void *context;
 486         void (*cont)(const struct firmware *fw, void *context);
 487         int uevent;
 488 };
 489
 490 static int
 491 request_firmware_work_func(void *arg)
 492 {
 493         struct firmware_work *fw_work = arg;
 494         const struct firmware *fw;
 495         int ret;
 496         if (!arg) {
 497                 WARN_ON(1);
 498                 return 0;
 499         }
 500         ret = _request_firmware(&fw, fw_work->name, fw_work->device,
 501                 fw_work->uevent);
 502         if (ret < 0)
 503                 fw_work->cont(NULL, fw_work->context);
 504         else {
 505                 fw_work->cont(fw, fw_work->context);
 506                 release_firmware(fw);
 507         }
 508         module_put(fw_work->module);
 509         kfree(fw_work);
 510         return ret;
 511 }
 512
 513 /**
 514  * request_firmware_nowait: asynchronous version of request_firmware
 515  * @module: module requesting the firmware
 516  * @uevent: sends uevent to copy the firmware image if this flag
 517  *      is non-zero else the firmware copy must be done manually.
 518  * @name: name of firmware file
 519  * @device: device for which firmware is being loaded
 520  * @context: will be passed over to @cont, and
 521  *      @fw may be %NULL if firmware request fails.
 522  * @cont: function will be called asynchronously when the firmware
 523  *      request is over.
 524  *
 525  *      Asynchronous variant of request_firmware() for contexts where
 526  *      it is not possible to sleep.
 527  **/
 528 int
 529 request_firmware_nowait(
 530         struct module *module, int uevent,
 531         const char *name, struct device *device, void *context,
 532         void (*cont)(const struct firmware *fw, void *context))
 533 {
 534         struct task_struct *task;
 535         struct firmware_work *fw_work = kmalloc(sizeof (struct firmware_work),
 536                                                 GFP_ATOMIC);
 537
 538         if (!fw_work)
 539                 return -ENOMEM;
 540         if (!try_module_get(module)) {
 541                 kfree(fw_work);
 542                 return -EFAULT;
 543         }
 544
 545         *fw_work = (struct firmware_work) {
 546                 .module = module,
 547                 .name = name,
 548                 .device = device,
 549                 .context = context,
 550                 .cont = cont,
 551                 .uevent = uevent,
 552         };
 553
 554         task = kthread_run(request_firmware_work_func, fw_work,
 555                             "firmware/%s", name);
 556
 557         if (IS_ERR(task)) {
 558                 fw_work->cont(NULL, fw_work->context);
 559                 module_put(fw_work->module);
 560                 kfree(fw_work);
 561                 return PTR_ERR(task);
 562         }
 563         return 0;
 564 }
 565
 566 static int __init
 567 firmware_class_init(void)
 568 {
 569         int error;
 570         error = class_register(&firmware_class);
 571         if (error) {
 572                 printk(KERN_ERR "%s: class_register failed\n", __FUNCTION__);
 573                 return error;
 574         }
 575         error = class_create_file(&firmware_class, &class_attr_timeout);
 576         if (error) {
 577                 printk(KERN_ERR "%s: class_create_file failed\n",
 578                        __FUNCTION__);
 579                 class_unregister(&firmware_class);
 580         }
 581         return error;
 582
 583 }
 584 static void __exit
 585 firmware_class_exit(void)
 586 {
 587         class_unregister(&firmware_class);
 588 }
 589
 590 fs_initcall(firmware_class_init);
 591 module_exit(firmware_class_exit);
 592
 593 EXPORT_SYMBOL(release_firmware);
 594 EXPORT_SYMBOL(request_firmware);
 595 EXPORT_SYMBOL(request_firmware_nowait);